js implements simple verification code_javascript skills-JS Tutorial-php.cn

js implements simple verification code_javascript skills

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Release： 2016-05-16 15:23:49

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Verification codes should be familiar to everyone. They are mainly for the security of the website and to prevent malicious registration and login. There are different ways to implement verification codes. The following is a verification code effect implemented using javascript for your reference. I hope it can be helpful to you.

Operation rendering:

The code is as follows:

<html>
<head>
<title>js验证码</title>
<style type="text/css">
.code 
{
 background:url(code_bg.jpg);
 font-family:Arial;
 font-style:italic;
 color:blue;
 font-size:30px;
 border:0;
 padding:2px 3px;
 letter-spacing:3px;
 font-weight:bolder;
 float:left;
 cursor:pointer;
 width:150px;
 height:60px;
 line-height:60px;
 text-align:center;
 vertical-align:middle;
}
a 
{
 text-decoration:none;
 font-size:12px;
 color:#288bc4;
}
a:hover 
{
 text-decoration:underline;
}
</style>
<script type="text/javascript">
var code;
function createCode() 
{
 code = "";
 var codeLength = 6; //验证码的长度
 var checkCode = document.getElementById("checkCode");
 var codeChars = new Array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 
      'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',
      'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'); //所有候选组成验证码的字符，当然也可以用中文的
 for(var i = 0; i < codeLength; i++) 
 {
  var charNum = Math.floor(Math.random() * 52);
  code += codeChars[charNum];
 }
 if(checkCode) 
 {
  checkCode.className = "code";
  checkCode.innerHTML = code;
 }
}
function validateCode() 
{
 var inputCode=document.getElementById("inputCode").value;
 if(inputCode.length <= 0) 
 {
  alert("请输入验证码！");
 }
 else if(inputCode.toUpperCase() != code.toUpperCase()) 
 {
   alert("验证码输入有误！");
   createCode();
 }
 else 
 {
  alert("验证码正确！");
 }    
}  
</script>
</head>
<body onload="createCode()">
<form id="form1" runat="server" onsubmit="validateCode()">
 <div>
  <table border="0" cellspacing="5" cellpadding="5" >
   <tr>
    <td></td>
    <td><div class="code" id="checkCode" onclick="createCode()" ></div></td>
    <td><a href="#" onclick="createCode()">看不清换一张</a></td>
   </tr>
   <tr>
    <td>验证码：</td>
    <td><input style="float:left;" type="text"  id="inputCode" /></td>
    <td>请输入验证码</td>
   </tr>
   <tr>
    <td></td>
    <td><input id="Button1" onclick="validateCode();" type="button" value="确定" /></td>
    <td></td>
   </tr>
  </table>
 </div>
</form>
</body>
</html>

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I hope this article will be helpful to everyone in learning javascript programming.